The main objectives of this research are to examine the current financing and organization mechanisms of health care delivery in Mexico (Public VS Private). More specifically this research focuses on the impact of actual public and private financing mechanisms on the access and utilization of health services by the various groups of the Mexican Population. The central hypothesis of this project is that the degree of reliance on the private sector by individuals in the various eligibility pools of the public sector will be related to differences in per capita expenditures in government programs, differences in utilization of services, and differences in satisfaction and self-perceived health status of the population among the four programs (IMSS, ISSSTE, ISSSTESON, & SSA). This relationship will be investigated by doing a survey of a representative sample of households in the state of Sonora, which in one of six Mexican states that borders the U.S.C., to determine their health care utilization history, perceived health status, levels of satisfaction for services received, and patterns of private expenditures. This will be combined and cross-validated with data from the government health institutions and the private sector physicians in the State of Sonora. An empirical and a systematic understanding of how the components of the entire system relate to each other will result from this research. There is growing interest in examining alternative plans of health care financing and services delivery in Mexico for more efficient use of scarce resources and more equitable access utilization of services. These plans are being discussed in Mexico but the absence of clear cut information on how the system works makes it difficult to design such programs. This research is intended to help solve this problem.